1. Field of the Invention
The present invention relates to valves for inflating tyres of tyred wheels, in particular tyres for vehicles, where the term “vehicles” means motor vehicles, vans, motorcycles, or in general means of locomotion on tyres.
In greater detail, the invention regards a valve designed for being used in the context of TPMS (Tyre Pressure Monitoring System) technology, in which electronic sensors for detection and transmission of certain operating parameters of the tyres, in particular pressure, but also, for example, temperature, are mounted directly on the valve itself, and the valve is fixed to the wheel by means of a hole made in the rim.
The valves used in the context of TPMS devices are normal valves of the clamp-in or snap-in type, i.e., of the type that can be associated to the rim of the wheel by means of screw-type or elastic snap clamping means.
The structure of the valve is associated to a transducer, supplied by a battery, which detects, by means of electronic sensors, the value assumed by parameters that are significant for proper operation of the wheel and enables radio transmission of the data collected to a reading control unit positioned, for example, on the instrument panel of the vehicle.
2. Description of the Related Art
According to the known art, illustrated for example in FIGS. 1 and 2, the valve-transducer assembly is mounted on the rim of the wheel in such a way that the valve projects outside the rim and the transducer is housed within the chamber delimited between the tyre and the rim itself so as to be tangential to the rim itself.
Currently, rubber-coated valves of the snap-in type are preferably used for light vehicles, and metal valves of the clamp-in type are preferably used for high-performance vehicles. Both have a shape with perfectly radial symmetry as regards the portion outside the rim, and the connection between the valve and the transducer, in order to constitute a valve-transducer assembly, can be of the type with screwed coupling, slot-in shape fitting, or co-moulding.
Said valve-transducer assemblies have some limits and disadvantages due above all to the impossibility of knowing the position assumed by the transducer inside the air chamber of the tyre when the assemblies are mounted on the wheel.
When, for example, inflation of the tyre mounted on the rim is automated, i.e., it is carried out on an industrial production line, in case the transducer is not positioned correctly in its seat, and is for example partially rotated, there is the risk, during pumping of the tyre, that the latter, by expanding, comes to strike against the transducer, thus breaking it.
In other cases, the centrifugal force of the wheel in motion leads the transducer, above all in the case of valves of a rubber-coated type, to rise with respect to the internal surface of the rim, moving it away from its plane of rest allowing it to turn and thus set itself out of its seat. When the tyre is being removed, since there is no reference of the position assumed by the transducer inside the air chamber, even the expert hands of a person skilled in the sector can cause impact of the edge of the tyre against the transducer, thus damaging it irreparably.
Valves with metal fixing of the clamp-in type are more rigid and less subject to rotations caused by the thrusts of the centrifugal force, but are in any case readily subject to possible damage: during final tightening of the nut with which the valve-transducer assembly is fixed to the rim, an improper dosing of the force risks causing rotation of the entire valve-transducer assembly, thus dislodging the transducer out of its seat, which can thus incur in the risks described above during tyre change.